I got together with my boyfriend over a year ago. He was very open and told me from the beginning away that he was bisexual. I accepted this thinking it would never be an issue or concern in our relationship, until the other night. We were on a night out and his new friend from his course was there (who is gay). My boyfriend got very drunk and said to me he fantasized about being with me and his friend at the same time. I’m not sure if he was joking because he was drunk or he actually wants this to happen. I have always thought that his friend might have had a little crush on my boyfriend, and now I’m feeling really worried about this, and it’s made me feel really awkward around my boyfriend and the friend. I don’t know if I should confront him about it and how to approach this issue.
Please help me!!!
What should I do?

I wouldn't confront him about it, as the word suggests that's a bit too confrontational and what you really want to do is tease out his true feelings on the matter. You could drop it into a conversation over the next day or two and see what he says. Doing it that way would give the impression that you weren't overly bothered by it and may make it more likely that he'll give you an honest response.

The alternative is that you sit him down and have a proper discussion about it where you tell him it's concerning you and you ask him about his true feelings. The potential issue with this approach is that you won't actually get his true feelings on the issue because he may tell you what needs to be said to placate you. Only you know your boyfriend so you'll need to pick your approach based on how you feel he'll respond.

I guess personally a concern I have with what you've said is whether he's considering the idea of a relationship with a man. I wonder if, in your boyfriend's head, a relationship or even an encounter with a man is not the same as cheating on you with another woman? I find it hard to imagine that he'd have been so open about fantasizing over a threesome with you and one of your female friends, yet he was quite open when it came to fantasizing about you, him and another man.

Christmas to a child is the first terrible proof that to travel hopefully is better than to arrive. - Stephen Fry.

The reason we struggle with insecurity is because we compare our behind-the-scenes with everyone else’s highlight reel. — Steve Furtick

I would suggest talking about this. A fantasy is one thing, everyone in a fantasy is happy and equal, and that sort of dream can actually make intimacy more passionate. Reality is loaded with problems from the start. If it was to happen then you and the friend would be likely to feel uncomfortable and insecure.

If you can feel sure he was talking about a fantasy, and realises it wouldn't work in real life, then there isn't a huge problem. If he really thinks it could, or worse, should happen at some stage, then there is a problem. It is just the same as wanting another girl in bed with you both, it's a recipe for problems.

That sort of set up works where two people both want it, feel very strong together, and set boundaries. Even then the spare person can feel lonely afterwards.

I really hope he will tell you he wanted to be honest and open about a fantasy, but knows it wouldn't work in the real world. I also hope that in that situation you feel safe and confident about the relationship.

whatever your problem someone else has been there and bears the scars.